A decision made

Ok, so I’ve come to a conclusion. I’ll use the Bordeaux etch method. Because it’s feasible. After following up in my research of the different types of “safer” etch methods, I hunted around for supplies. Because that’s truly the deciding factor here, availability and price. The Edinburgh etch method requires ferric acid, described here as “[a] somewhat water-soluble salt of iron and hydrochloric acid that has a tendency to become basic.” I wasn’t wild about the inclusion of hydrochloric acid but the author claims the method is non-toxic. That’s great but the Edinburgh etch requires a bit of a background in chemistry, including prepping the solution for use, beyond adding one part to another—and then purchasing test strips to determine the optimum strength.

Um, no thanks. According to Von Slatt, all one has to do is add a lot of Root Kill to a tub of water and then hook it up to a battery. So, the Bordeaux etch it is. It requires copper sulphate which is available in the gardening department as a root killer or as a spray to combat mildew. Cedric Green argues against using a solution like those I just mentioned because they contain additives but upon reviewing Von Slatt’s results, I’ve decided his method is good enough for me too. I'll just try to find a nearly pure copper sulphate product.

If I want to etch mild steel (iron) and zinc I can add an equal quantity of salt and if I want to etch aluminum I add an equal amount of sodium bisulphate. After another Google search I found this to be used for pool maintenance and is commonly referred to as “dry acid” because it’s, well, not liquid.

Beyond this, I found out that all metals involved in the etch must be of the same type otherwise it’ll become electroplating rather than etching. So, varnishing components may be in my future. I’m still going to try a salt water etch, because I’m already set up for it. I hope to do that tomorrow.